Many of the medical care products, protective wear garments, mortuary and veterinary products, and personal care products in use today are available as disposable products. By disposable, it is meant that the product is used only a few times, or even only once, before being discarded. Examples of such products include, but are not limited to, medical and health care products such as surgical drapes, gowns and bandages, protective workwear garments such as coveralls and lab coats, and infant, child and adult personal care absorbent products such as diapers, training pants, incontinence garments and pads, sanitary napkins, wipes and the like. These products must be manufactured at a cost which is consistent with single- or limited-use disposability.
Nonwoven fibrous webs formed by extrusion processes such as spunbonding and meltblowing, and by mechanical dry-forming process such as air-laying and carding, used in combination with thermoplastic film or microfiber layers, may be utilized as components of these disposable products since their manufacture is often inexpensive relative to the cost of woven or knitted components. A layer of film or microfibers may be used to impart liquid barrier properties, and an elastic layer (elastic film or elastic microfibers, for example) may be used to impart additional properties of stretch and recovery. However, films in general and elastic layers in particular, whether a film layer or a microfiber layer, often have unpleasant tactile aesthetic properties, such as feeling rubbery or tacky to the touch, making them unpleasant and uncomfortable against the wearer's skin. Nonwoven fibrous webs, on the other hand, have better tactile, comfort and aesthetic properties.
The tactile aesthetic properties of elastic films can be improved by forming a laminate of an elastic film with one or more non-elastic, extensible materials, such as nonwoven fibrous webs, on the outer surface of the elastic material.
Nonwoven fibrous webs formed from non-elastic polymers such as, for example, polyolefins are generally considered non-elastic. This lack of elasticity may restrict these nonwoven web materials to applications where elasticity is not required or desirable. When non-elastic nonwoven webs are laminated to elastic materials, the resulting laminate may also be restricted in its elastic properties.
Elastic laminate materials of elastic and non-elastic materials have been made by bonding the non-elastic material or web to the elastic material in a manner that allows the entire laminate or composite material to stretch or elongate so it can be used in disposable products. In one such laminate material, disclosed, for example, by Vander Wielen et al. U.S. Pat. No. 4,720,415, issued Jan. 19, 1988, a non-elastic web material is bonded to an elastic material while the elastic material is held stretched so that when the elastic material is relaxed, the non-elastic web material gathers between the bond locations, and the resulting elastic laminate material is stretchable to the extent that the non-elastic web material gathered between the bond locations allows the elastic material to elongate.
In another such elastic laminate material, disclosed for example by U.S. Pat. Nos. 5,336,545, 5,226,992, 4,981,747 and 4,965,122 to Morman, the non-elastic web material is necked (that is, is elongated in one direction, usually the machine direction, causing rugosities to form across the web) and is joined to the elastic material while in the non-elastic material is in the necked or elongated condition. The non-elastic material is then able to be extended in the direction perpendicular to the direction of necking, allowing for extensibility of the laminate. However, since these elastic laminate materials are often utilized in limited- or single-use disposable products, there remains a strong need for reducing the cost of producing these materials.